Originating or formed in a different place and transported to where it is now found, used for rocks, fossils, or organisms.
From Greek allo- (other) + chthon (earth) + -ous (adjective suffix). The adjective form of allochthon, widely used in geology and paleontology.
Fossils can be 'foreigners' too—an allochthonous fossil might have been swept downstream or pushed miles away before fossilizing, giving paleontologists tricky puzzles to solve!
Complete word intelligence in one call. Free tier — 50 lookups/day.